Editing Georges Cuvier (section)

=== Extinction ===
{{more citations needed section|date=April 2017}}
[[File:Anoplotherium_1812_Skeleton_Sketch.jpg|thumb|left|Georges Cuvier's 1812 skeletal reconstruction of ''[[Anoplotherium]] commune''. The stratigraphy and lack of modern analogue in the extinct mammal was proof of extinction and ecological succession.]]
Early in his tenure at the National Museum in Paris, Cuvier published studies of fossil bones in which he argued that they belonged to large, extinct quadrupeds. His first two such publications were those identifying mammoth and mastodon fossils as belonging to extinct species rather than modern elephants and the study in which he identified the ''Megatherium'' as a giant, extinct species of sloth.<ref>{{Cite book|title=Georges Cuvier : an annotated bibliography of his published works|last=Chandler.|first=Smith, Jean|date=1993|publisher=Smithsonian Institution Press|isbn=978-1560981992|location=Washington|oclc=25367530|url-access=registration|url=https://archive.org/details/georgescuvierann00smit}}</ref> His primary evidence for his identifications of mammoths and mastodons as separate, extinct species was the structure of their jaws and teeth.<ref>{{Cite book|last=Cuvier|first=Georges|orig-year=1796|year=1998|chapter=Memoir on the Species of Elephants, Both Living and Fossil|title=Fossil Bones, and Geological Catastrophes|doi=10.7208/chicago/9780226731087.001.0001|isbn=9780226731070}}</ref> His primary evidence that the ''Megatherium'' fossil had belonged to a massive sloth came from his comparison of its skull with those of extant sloth species.<ref>{{Cite journal|last=Cuvier|first=Georges|date=1796|title=Note on the skeleton of a very large species of quadruped, hitherto unknown, found in Paraguay and deposited in the Cabinet of Natural History in Madrid.|journal=Magasin Encyclopédique}}</ref>

Cuvier wrote of his paleontological method that "the form of the tooth leads to the form of the [[condyle]], that of the [[scapula]] to that of the nails, just as an equation of a curve implies all of its properties; and, just as in taking each property separately as the basis of a special equation we are able to return to the original equation and other associated properties, similarly, the nails, the scapula, the condyle, the femur, each separately reveal the tooth or each other; and by beginning from each of them the thoughtful professor of the laws of organic economy can reconstruct the entire animal."<ref>{{cite book|url=https://archive.org/details/essayontheoryea00mitcgoog|title=Essay on the Theory of the Earth|last=Georges Cuvier|first=Robert Jameson|date=1818|publisher=Kirk & Mercein|others=University of California|pages=98–99}}</ref> 

However, Cuvier's actual method was heavily dependent on the comparison of fossil specimens with the anatomy of extant species in the necessary context of his vast knowledge of animal anatomy and access to unparalleled natural history collections in Paris.<ref>{{Cite book|title=Georges Cuvier, zoologist a study in the history of evolution theory.|author=Coleman, William|date=1964|publisher=Harvard University Press|isbn=9780674283701|location=Cambridge, Massachusetts|pages=119–122|oclc=614625731}}</ref> This reality, however, did not prevent the rise of a popular legend that Cuvier could reconstruct the entire bodily structures of extinct animals given only a few fragments of bone.<ref>{{Cite book|title=Show me the bone : reconstructing prehistoric monsters in nineteenth-century Britain and America|last=Gowan|first=Dawson|isbn=9780226332734|location=Chicago|oclc=913164287|date = 21 April 2016}}</ref>

At the time Cuvier presented his 1796 paper on living and fossil elephants, it was still widely believed that no species of animal had ever become extinct. Authorities such as Buffon had claimed that fossils found in Europe of animals such as the [[woolly rhinoceros]] and the mammoth were remains of animals still living in the tropics (i.e. [[rhinoceros]] and [[elephant]]s), which had shifted out of Europe and Asia as the earth became cooler.

Thereafter, Cuvier performed a pioneering research study on some elephant fossils excavated around Paris. The bones he studied, however, were remarkably different from the bones of elephants currently thriving in India and Africa. This discovery led Cuvier to denounce the idea that fossils came from those that are currently living. The idea that these bones belonged to elephants living – but hiding – somewhere on Earth seemed ridiculous to Cuvier, because it would be nearly impossible to miss them due to their enormous size. The ''Megatherium'' provided another compelling data point for this argument. Ultimately, his repeated identification of fossils as belonging to species unknown to man, combined with mineralogical evidence from his stratigraphical studies in Paris, drove Cuvier to the proposition that the abrupt changes the Earth underwent over a long period of time caused some species to go extinct.<ref>{{cite book|url=https://archive.org/details/essayontheoryea00mitcgoog|title=Essay on the Theory of the Earth|last=Georges Cuvier|first=Robert Jameson|date=1818|publisher=Kirk & Mercein|others=University of California}}</ref>

Cuvier's theory on extinction has met opposition from other notable natural scientists like Darwin and [[Charles Lyell]]. Unlike Cuvier, they didn't believe that extinction was a sudden process; they believed that like the Earth, animals collectively undergo gradual change as a species.  This differed widely from Cuvier's theory, which seemed to propose that animal extinction was catastrophic.

However, Cuvier's theory of extinction is still justified in the case of mass extinctions that occurred in the last 600 million years, when approximately half of all living species went completely extinct within a short geological span of two million years, due in part by volcanic eruptions, asteroids, and rapid fluctuations in sea level. At this time, new species rose and others fell, precipitating the arrival of human beings.
Cuvier's early work demonstrated conclusively that extinction was indeed a credible natural global process.<ref>{{harvnb|Rudwick|1997|pp=22–24}}</ref> Cuvier's thinking on extinctions was influenced by his extensive readings in Greek and Latin literature; he gathered every ancient report known in his day relating to discoveries of petrified bones of remarkable size in the Mediterranean region.<ref>{{harvnb|Mayor|2011|pp=6, 8, 202–207}}</ref>

Influence on Cuvier's theory of extinction was his collection of specimens from the New World, many of them obtained from Native Americans. He also maintained an archive of Native American observations, legends, and interpretations of immense fossilized skeletal remains, sent to him by informants and friends in the Americas. He was impressed that most of the Native American accounts identified the enormous bones, teeth, and tusks as animals of the deep past that had been destroyed by catastrophe.<ref>{{harvnb|Mayor|2005|pp=2,61–63, 94–95}} and {{harvnb|Mayor|2008|pp=163–82}}</ref>